Water…

What are the Properties of Water? 1

How do bugs walk on water?

What is happening? How does a paper towel “slurp up” liquid?

Why the curve?

What is weird about water? Do you know how magnets work? Opposite magnets attract each Water acts like a magnet… Water has opposite charges at opposite ends This is called Polarity

Water molecules act like magnets Polarity causes: Cohesion & Adhesion & Surface Tension

Cohesion Attraction between particles of the same substance (why water is attracted to itself) Think “co-operate” (work together) Results in Surface tension Produces a surface “film” on water that allows insects to walk on the surface of water 1

Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND

Surface Tension The “membrane” at the surface of the water is called “Surface Tension”

Bugs and more! - Cohesion Jesus Christ Lizard and this too!

Water acts like a magnet Water molecules have a positively charged side and a negatively charged side When molecules come together, they stick like metal to a magnet

Adhesion Attraction between particles of water and other substances Think “adhesive tape” (sticks to other stuff) Results in water droplets sticking to things despite gravity Results in Capillary Action Water “climbing” against gravity Produces a curved surface called a Meniscus Water molecules are attracted to the molecules in a graduated cylinder 1

Adhesion Causes Capillary Action Adhesion gives water the ability to “climb” structures... That's how the paper towel seems to “slurp-up” liquids!

Attach to a silken spider web Form spheres & hold onto plant leaves Adhesion Also Causes Water to … Attach to a silken spider web Form spheres & hold onto plant leaves

High Specific Heat Water is able to absorb a lot of heat before it gets hot enough to boil 1

High Heat of Vaporization What is vaporization? Water requires a lot of energy to change a molecule of liquid water into a molecule of water vapor (gas) 1

Less Dense as a Solid Why do ice cubes float on water? In liquids and gases, the molecules are moving... When frozen, water molecules are “locked” in place... and the polarity causes water to attract and repel at the same time! 1

When water freezes... Ice actually has a very different structure than liquid water The molecules align themselves in a regular lattice pattern with “air pockets” between the molecules So, liquid water is more dense than frozen! Which is why ice floats on water!